Process of making piston rings



Nov. 1 I", "1924.. 1,515,472

H. S. FRANK PROCESS OF MAKING PISTON RINGS Filed Sent. 16. 1920 PatentedNov. 11, 1924:.

HARRY S. FRANK, O'F WOODMERE, NEW YORK.

PROCESS OF MAKING PISTON RINGS.

To all whom it may concern:

Be it known that I, HARRY S. FRANK, a citizen of the United States, andresident of WVoodmere, L. I., in the county of Nassau and State of NewYork, have invented certain new and useful Improvements in Processes ofMaking Piston Rings, of which the following is a specification.

This invention relates in general to the process of making piston ringsand partic ularly to a method of producing uniformly expanding ringssimilar to that set forth in my United States application, Serial No.325,711 filed September, 1919.

Its primary object is to provide an effective and comparativelyinexpensive novel process of producing piston rings which will uniformlyexpand at all points of their circumference, and therefore afford aperfeet, tightfit within the cylinder wall for which they are intended,thus exerting an equal radial outward pressure at all points of theirperipheries against the cylinder wall.

The foregoing and a number of other important objects will be readilydisclosed and understood from the following description and theaccompanying drawings, serving fOr explanatory purposes, in which:

Figure 1 represents a concentric, gapped ring blank in closed, freelyassumed shape.

Figure 2 illustrates how theoretically a ring is clamped together at itsgap, thus permitting it to freely assume a natural ring-like shape.

Figure 3 is a diagrammatical illustration of a device for temporarilyreceiving a ring blank and facilitating its freely assuming a ring-likeshape and with its radial expanding force in equilibrium.

Figure 4 is a side elevation of a clamping and centering device forretaining the ring in its originally assumed natural shape andfacilitating the reducing of the rings outer circumference to a truecircle of desired diameter.

Figure 5 is a plan view thereof.

Figure 6 is a cross sectional view of a reclamping and centering devicefor retaining the outwardly reduced ring in its originally closed shapeand facilitating the rings inner circumference being turned to desireddimension.

In Figure 3 a receiver 10 is diagrammatt cally shown in which is mounteda plurality of radially movable blocks 11. Only a Serial No. 410,620.

small number of these blocks is illustrated but this will suffice forexplaining the working principle of the device.

A severed or gapped ring 12, fixedly held together at its ends is placedinto the receiver and the blocks are gradually moved inward untilabutting with the rings outer circumference. Now the ring ends arefreed, while blocks 11 are holding the ring in the exact shape asthatwhen the ring was originally introduced while held together at itsends.

In quantity manufacture it was found that a large percentage of rings ofthe like sizes will assume the like curvatures when closed at andfixedly held together at their ends. For such rings of equal sizes,receivers with permanently attached ribs or blocks 11 can be used.

When a plurality of such rings of equal size and equal curvature havebeen placed into the receiver, a clamping device, shown in Fig. 4, isintroduced into the receiver, and the rings are fixedly clamped togetherwhile retaining the shape which they freely assumed, when originallyheld together at their ends. This clamping device as shown comprisesdisks or washers 13, through the center opening of which passes athreaded centering spindle 14. Nuts 15 serve for tightening disks 13against the faces of the ring.

When introducing the clamping device into the receiver, it is obviousthat before clamping the ring the device must be first centered in thereceiver. The centering spindle 14 is provided with any suitablecentering means indicated at 16, by means of which it may be held in amachine, for instance, in a lathe, milling machine, grinder or the like.

When correctly centered, the ring 12 is now turned or otherwise reducedat its outer circumference to a true circle of the desired diameter forwhich the ring is intended.

Thereafter the reduced ring, without having been released from itsoriginally assumed shape, is placed and centered in another clampingcontrivance shown in Fig. 6, which I will term a re-clamping device. Itconsists of a tubular member 17, externally threaded at one of its ends18 and provided with a flat annular seat 19. 4 The other; end of theire-clamping device is preferably smooth and fits into a socket providedwith a centering stem 21. Engaging the threaded end 18 of sleeve ortubular member 17 is an open cap 22 provided with an annular seat 23.

Before attaching the cap, the centering device (shown in Fig. 4) holdingring 12 is placed bodily into sleeve 17 so that one face of the ringabuts with face or seat 19 of the sleeve. The ring is then properlycentered and the cap is screwed on the sleeve until face firmly clampsthe ring; in position.

Now the nuts 1.5 of the clamping" device are loosened and disks 13removed. The sleeve is ,then centered in socket 20 and the innercircumference of the ring; is machined to the desired dimensions.

It is obvious that the above operations may be reversed in so far as itis more cX- peditio'us to first center the receiver shown in Fig. 3,into which a. ring was placed in the manner stated above. bore the ringsinner circumference and then transfer it to an arbor similar to thatshown in s2 and finish its outer circumference, while held in the arbor.

Where a number of rings of the same curvatureare retained in a receiver,their inner and outer surfaces may be machined in multiple in the samemanner.

Before the ring is turned, it will be advantageous to roughly face thering, but this operation may be done when the ring is already closed.The finishing and facing: cf the may take place when the ring isreleased after the machining operations.

[have found it sometimes preferable to roughly finish the ring blankbefore turning: it to desired diameter. rrlso roughly cutting or gappingit and later finishing the gapped ends may prove of benefit in somecases.

In Fig. 2 a temporary clampinn device 21- of simple construction isshown to indicate that the closing; of the gapped ring); may beaccomplished in any desired manner as long as the closing operation ofthe ring is unobstructed in any way, thus allowingthe ring to freelyassume a so to speak natural shape, whereby an equilibrium of its radialexpanding forces is established.

In order to simplify and to reduce my process to practical shopoperations a variety of combinations in handling the ring blank may beemployed. One of the preferred ways I have tested is to first applyexternal pressure against the severed or gripped ring: blank, preferablyin tangential direction to its gap, so as to close its ends, retaining:the ends in closed relation by means of a device 24]: or similarcontrivances, depending upon the form of the severed ends of the blank.When the ends of the ring are thus securely clamped together, Idiscontinue the formerly applied external pressure upon the ring. By sodoing, the blank is retained in a closed ringdike, somewhat oval shape,which it is permitted to freely or naturally assume, while its radialexpanding forces in consequence of the freely assumed shape will be inequilibrium at all points of its cir cuinferenc'e.

Now a retainer similar to that disclosed in Fig. is employed. The ringheld in its freely assumed shape by clamp 2a or similar devices, isplaced in the retainer and centered therein by way of a plurality ofradially movable blocks indicated at ill. When these blocks have beenbrought to bear snugly against the closed held ring, without in any wayaltering its freely assumed shape, and assuring the retention of thatfreely assumed shape of the ring, the clamping; device holding its endstogether is re leased and removed.

This operation may be repeated until a sutficient number of rings hasbeen placed in the receiver so as to abut. An arbor with end platessimilar to that indicated at 1.3 in Fig. iis then passed through thereceiver and the rings clamped firmly together without disturbing thefreely assumed individual shapes of any of the rings held in place bythe series of blocks Thereafter the blocks are loosened and the clampedtogether rings may be removed from the receiver, centered and theirouter circumference reduced. to perfect circular shape of the diameterfor which they are intended by either turning, grinding, polishing orotherwise machining or treating); the rings.

Havingr reduced their outer circumference to a perfect desired shape therings may either be re-clamped without releasing them from the arbor inthe manner explained in connection with Figs. 4t and 6, or they may hereleased from the arbor and filed individually into a cylinder of acorresponding perfect circular shape of the desired diameter. where theyare again clamped together but in such a way as to facilitate theirinner circumference being shaped by turning, grinding. finishing" orotherwise machining or treating: to the desired form.

it is obvious that the operations of reducinp; the ring; body to a coremay be reversed by first individually cl. ring the gripped ring blank inthe manner already described. filing it in its closed form in: areceiver like that shown in Fig. 3, adjusting; the blocks '11 to theperiphery of the freely assumed ring-like shapes. thus maintaining theseoriginally assumed ring shapes, releasing the devices clamping orholding the ring ends together, and clamping the ring shapes within thereceiver so as to facilitate their inner circumference being easilymachined to desired form.

Jo i

Then a cylinder or arbor of a diameter corresponding to or being lessthan the inner diameter of the rings may be inserted. and the ringsclamped together and centered without disturbing their outer freelyassumed circumferential shape and, thus clamped, removed from thereceiver. Now their outer circumference is reduced to perfect circularshape of the desired dimension, whereafter the rings are released.

In practice I have found that the deviations of ring blanks prepared forone desired size is so small or may be made as small so that it becomespracticable to elimi nate individually adjustable blocks 11 (Fig. 3) ina receiver, and substitute therefor longitudinal ribs, shaped and soarranged as to conform with the average individually freely assumedshape of the rings.

\Vhen filing the closed rings in such a receiver and when the rings donot exactly fit therein, a slight twist of the ring brings it in fullcontact with. the ribs or blocks suflicient to retain it in the freelyassumed shape when clamp 24 or a similar device holding the rings inclosed position is released.

When blanks. prior to their being closed, are roughly finished,receivers may be used of a desired inner shape, for instance, cylinderswith an oval inner opening corresponding to the average form freelyassumed by roughly finished ring blanks when closed and temporarilyclamped in the manner explained herein.

In the drawings are disclosed two typical ring blank shapes havingso-called lapjoint cuts. It is self-understood however, that my processmay be employed in the manufacture of rings for any purpose and of anydesired shape, form, or cross-sections and having various kinds ofsevered or split joints, such, for instance, as straight, diagonal,interlocking, spiral or other known splits or cuts.

Having thus described my invention, I claim:

1. The process of equalizing all the forces in a closed, apped pistonring blank, having overlapping ends, which comprises holding said blanktogether at one point of its overlapping ends.

2. The process of producing piston rings equally expanding at all pointsof their circumference, which comprises, severing a ring blank,providing its ends with portions designed to over-lap, closing the ringand holding its overlapping ends together at a single point. thuspermitting the ring to substantially freely assume a ring-like shape,clamping the rings for the purpose of machining it without altering itsassumed shape.

3. The process of producing piston rings equally expanding at all pointsof their circumference, which comprises, severing a ring blank,providing its ends with portions designed to overlap, closing the ringand holding its overlapping ends together at a single point, thuspermitting the ring to substantially freely assume a ring-like shape,clamping the ring circumferentially without altering its assumed shape,releas ing its ends, and machining it while thus clamped.

4-. The process of producing piston rings equally expanding at allpoints of their circumference, which comprises closing and fixedlyholding a severed ring blank having overlapping ends, at one point ofits severed ends, thus permitting it to freely assume a naturalring-like shape in which the expanding forces are equalized, clampingthe ring circumferentially without altering its ring-like shape,releasing its overlapping, fixedly held ends, and machining it While thering is thus clamped.

5. The process of producing piston rings equally expanding at all pointsof their circumference, which comprises closing and chucking for thepurpose of machining a severed ring blank in such a Way as to correspondin shape to a severed ring blank which is fixedly held together at onepoint of its severed ends.

6. The process of producing piston rings equally expanding at all pointsof their circumfer-ence. which comprises closing and fixedly holding forthe purpose of machinmg, a severed ring blank having overlapping ends,in such a way as to correspond in shape to a severed ring blank which isheld at one point of its severed ends and which is thus permitted tofreely assume a natural, ring-like form in which the expanding forcesare equalized.

7. The process of making piston rings, which comprises closing andsubsequently chucking for the purpose of machining a plurality ofsevered piston ring blanks having overlapping ends, in such a manner asto correspond in shape to a plurality of individual severed ring blankshaving overlapping ends and which are held singly to get-her at onepoint of their ends, whereby the rings would freely assume natural,ringlike shapes in which the expanding forces are equalized.

Signed at New York, in the county of New York, and State of NewYorkxthis 17th. day of August, A. D. 1920.

HARRY S. FRANK.

